Multimedia technologies have become more and more ubiquitous. A multimedia experience refers to the use of media in an interactive environment. The media generally include one or more types of information content, including for example, text, audio, graphics, animation, and video. During a multimedia experience, the media are presented to an end-user according to a logical sequence that can be affected by the end-user's actions.
It is desirable to provide end-users with responsive and uninterrupted playback of media in a multimedia experience. However, media typically can not be accessed instantaneously during a multimedia experience. For example, media may be stored on a remote host computer, requiring that the media be sent over a network (such as the Internet) to the end-user's computer before it can be played. There is an inherent lag between the time data is requested from a remote host and when it is received and ready to be accessed by the multimedia experience. This time lag can be significant, depending on such factors as network bandwidth and data size.
In order to avoid playback interruptions during a multimedia experience, it is known to provide algorithms to determine which media assets to request in advance so that they will be ready for playback if they are needed. The retrieval of data in advance (while other playback activity takes place) is referred to as “preloading.” In general, preloading attempts to ensure that media playback proceeds smoothly and without interruption when media resources are not immediately available. A preloading scheme is, by definition, a set of algorithms that implement rules for determining what media assets to request and when to request them.
In some environments, such as the Macromedia Flash® authoring environment, a multimedia experience proceeds along one or more linear timeliness For linear multimedia experiences, a preloading scheme can anticipate with certainty before the start of the multimedia experience which media will be played back, and in what order. In a multimedia experience that contains conditional branching, i.e., a non-linear multimedia experience, making such advance predictions are difficult. Additionally, often only a part of the total amount of media referenced by a non-linear multimedia experience will be played back during any one playback session. Thus, to request a transfer of all media referenced by the multimedia experience would be inefficient and, in scenarios where bandwidth expenses exist, unnecessarily costly. In order to avoid playback interruptions, a default preloading scheme (as described further below) can be implemented that seeks to strike a balance between requesting too much media that is never ultimately played and requesting enough media to ensure that what actually gets played is available the moment it is needed.
There are situations, however, when default preloading schemes cannot accurately predict how soon to preload certain media assets, such as if those assets are unusually large, or if the time when they'll be played arrives unusually quickly. In such cases, an undesirable break in playback occurs while the remainder of the media is received. To mitigate this problem, it is of considerable benefit for designers to be able to override or customize the default preloading scheme as they deem necessary, in order to force the preloading of certain media assets sooner or later than would otherwise be the case. In other environments, a default preloading scheme may not even exist and the designer may wish to provide a custom preloading scheme of his own. There is a need, therefore, for a method that can be used to overcome the disadvantages discussed above.